Pediatric nutritional products, particularly infant formulas, are designed to mimic human milk as closely as possible. Human milk contains numerous macro and micronutrient components, the identity and function of which are still being discovered and studied. One essential macronutrient important for growth and development is protein. Human milk contains both intact proteins and peptides, and has a unique peptide profile that contributes to many of the health benefits of human milk. Some of the peptides in human milk (molecular weight of less than 12 kDa, and more particularly, less than 5 kDa) have been identified as fragments of human milk β-casein and other proteins, such as IGF-1, TGF-β, and ghrelin. Certain human milk peptides derived from human milk β-casein have been sequenced and their properties identified, including isoelectric point (pI), solubility and charge at neutral pH determine the cationic/anionic nature of a particular peptide.
In addition to having a unique peptide profile, the nitrogen distribution of human milk is unique. Approximately 75% to 80% of total nitrogen content of human milk is provided by intact proteins, and approximately 20% to 25% of total nitrogen is provided by non-protein nitrogen. Non-protein nitrogen in human milk includes peptides, free amino acids, polyamines, nucleotides, urea, and sialic acid. More specifically, approximately 10% to 15% of total nitrogen in human milk is provided by the non-protein nitrogen small peptides and free amino acids. Human milk peptides also provide important functional benefits, including antioxidant, antimicrobial, antiviral, angiotension converting enzyme (ACE) inhibitory and immunomodulatory activities. Furthermore, human milk peptides are believed to contribute additional benefits to human milk, such as improving sleep and reducing stress in infants.
Routine pediatric milk based nutritional compositions, such as those not intended for allergic individuals, generally include intact protein sources such as whey, casein or mixtures of both. Caseins of bovine milk include αS1, αS2, κ and β-casein. Bovine milk contains similar amounts of β-casein as human milk and has a sequence homology to human β-casein of about 50%. Bovine whey includes several major milk proteins such as β-lactoglobulin, α-lactalbumin, bovine serum albumin, and immunoglobulins.
Nevertheless, such routine nutritional compositions based on intact casein and/or whey do not have a peptide or nitrogen distribution profile similar to that of human milk, nor do they provide as many beneficial functions that are found in human milk. Accordingly, it would be advantageous to provide a pediatric nutritional composition that more closely mimics the nitrogen distribution profile of human milk. Furthermore, it would be desirable to provide a pediatric nutritional composition that closely mimics the peptide profile of human milk by including functional peptides that are similar in structure and/or function to the peptides found in human milk, such as peptides having antioxidant, antimicrobial, antiviral, ACE inhibitory and immunomodulatory activities. The present disclosure addresses these needs.